Gene Expression Worksheet

Visit the PHET Interactive Simulations website from the University of Colorado Boulder.

Click “Expression.”

Observe “Gene 1.”

What type of biomolecule is “Gene 1”? How do you know?

The biomolecule is a nucleic acid. Specifically, the biomolecule is DNA since it is double-stranded, with the two double-helix strands running in opposite directions.

Observe the two regions on “Gene 1.”

What do you think each region does with respect to gene expression?

On the one hand, I anticipate the transcribed region to allow the synthesis of a certain RNA molecule and hence direct the expression of the encoded gene.

On the other hand, the regulatory region would be responsible for regulating RNA synthesis. Accordingly, I anticipate this region to prevent and/or allow the binding of RNA polymerase, which catalyzes the transcription process.

Drag and drop an “RNA Polymerase” onto the space between the “Regulatory Region” and “Transcribed Region.” Observe for 30 seconds.

What happened? What do you notice?

The RNA polymerase did not bind to this space; instead, it moved away from the gene.

Drag and drop the “Negative Transcription Factor” into the “Regulatory Region.” Again, drag and drop the “RNA Polymerase” back into its space from before. Observe for 30 seconds.

What happened? What do you notice?

The Negative Transcription Factor binds to the Regulatory Region. Still, the RNA polymerase did not bind to the space between the Regulatory Region and the Transcribed Region.

Put the “RNA Polymerase” and “Negative Transcription Factor” back in the toolbox by dragging and dropping them back to where they were.

Drag and drop the “Positive Transcription Factor” into the “Regulatory Region.” Again, drag and drop the “RNA Polymerase” back into its space. Observe for 30 seconds.

What happened? What is different than before?

After the Positive Transcription Factor was dropped into the Regulatory Region, the RNA Polymerase successfully binded to the space. As a result, the DNA unwound, and an mRNA molecule was produced. The RNA polymerase then detached from the region.

Drag and drop a “Ribosome” onto the newly created “mRNA.” Observe for 30 seconds.

What happened?	After adding a ribosome to the newly formed mRNA, the mRNA moved through the folds of the ribosome and formed a diamond-shaped protein.
What was produced?	This process produced a diamond-shaped protein. Notably, an additional diamond-shaped protein was produced whenever the mRNA molecule came into contact with the ribosome.

Consider your readings from this week about molecular microbiology.

How do your observations relate to the readings from this week? Use examples and be sure to discuss at least the following concepts:

· Genes

· RNA

· Protein Synthesis

The observations relate to this week’s readings as they bring to light the concept of the central dogma of biology, where the information in genes is converted to proteins. Notably, genes are the functional unit of genetic information and make up parts of chromosomes (Madigan et al., 2021). This genetic information is contained in nucleic acids, DNA and RNA. DNA is double-stranded and contains the genetic blueprint of a cell, while RNA, which is produced during transcription, is single-stranded and contains a copy of this genetic blueprint (Madigan et al., 2021).

The flow of genetic information from DNA to proteins follows three main stages: replication, transcription, and translation. Replication involves the duplication of the DNA double helix, a process catalyzed by the DNA polymerase. Next, transcription involves the synthesis of RNA from DNA. This process requires the enzyme RNA polymerase, which was showcased in the simulation. Evidently, an mRNA molecule was formed only after the RNA polymerase bound to the gene region between the Regulatory and the Transcribed Region.

Lastly, translation involves protein synthesis, where an mRNA molecule assembles an amino acid into a polypeptide. In the simulation, a diamond-shaped protein was produced after the newly formed mRNA molecule passed through the ribosome folds. Accordingly, this relates to the weekly readings that note that translation occurs in the ribosomes (Madigan et al., 2021).